Thiol derivatives of olefin-maleic anhydride copolymers

ABSTRACT

Olefin-maleic anhydride copolymers are provided wherein a portion of the anhydride moieties are converted to thio anhydride moieties. Other thio derivatives are also provided including the thio acids. These compounds are effective as stabilizers in vinyl type resins, particularly vinyl chloride polymers and can also serve as chelating agents.

United States Patent Stamm [451 'Apr. 3, 1973 I [54] THIOL DERIVATIVES OF OLEFIN- [56] References Cited MALEIC ANHYDRIDE COPOLYMERS v UNITED STATES PATENTS [75] lnventor: Walter Stamm, Tarrytown, N.Y.

' 3,574,172 ll 1970 S ..2 79 [73] Assignee: Stauiter Chemical Company, New I 60/ York Primary Examiner-Samuel H. Blech [22] Filed: Mar. 18, 1971 Assistant Examiner-C. U.Seccuro Attorney-Robert C. Sullivan, Donald M. MacKay, [21] Appl' 76342 Paul .I. Juettner, Daniel C. Block, Wayne C. Jaeschke Related U.S. Application Data and Martin Goldwasser I [62] pig/55302110? Ser. No. 770,798, 0a. 25, 1968, Pat. No. ABSTRACT Olefin-maleic anhydride copolymers are provided [52] U.S. Cl. ..260/897 C, 260/897 B, 260/895, wherein a portion of the anhydride moieties are con- 260/896, 260/785 T, 260/785 R, 260/79.5 verted to thjo anhydride moieties. Other thio deriva- [51] Int. Cl. ..C08f 29/12 tives are also provided including the thio acids. These [58] Field of Search ..260/897, 78.5 T compounds are effective as stabilizers in vinyltype resins, particularly vinyl chloride polymers .and can also serve as chelating agents.

9 Claims, No Drawings 'IIIIOL DERIVATIVES F OLEFIN-MALEIC ANIIYDRIDE COPOLYMERS RELATED APPLICATION This application is a division of application Ser. No. 770,798, filed Oct. 25, 1968 now U.S. Pat. No. 3,629,205.

The present invention relates to novel compositions of matter. More particularly, this invention relates to the thio derivatives of lower alpha-olefin-maleic anhydride copolymers.

The novel compositions of this invention find particular utility as stabilizers for vinyl resins, as rubber accelerators and curing agents, as chelating agents and as ion exchange resins of peculiar selectivity.

The ethylene-maleic anhydride copolymers and the isobutylene maleic anhydride copolymers are well known commercially available materials.

Certain of these copolymers of ethylene and maleic anhydride and the methods for the preparation thereof are set forth in U.S. Pat. No. 2,378,629. These resins are commercially available under the trademark name EMA. The methyl vinyl ether-maleic anhydride YM YM :1

wherein R is a lower alkylene group of from one to five carbon atoms inclusive, a is an integer having a value of from 0 to l and b is an integer having a value of from 0 to 1 such that when a=l b also =1, M is a monovalent cation having a molecular weight less than 40, Y and Y are chalcogens having molecular weights less than 34 with the provision that at least one Y per molecule must be sulfur and in Formula III above at least one !YII o V-YM per molecule must be As will be appreciated in Formulas I, II, and III above, the substituent (O),,(CH ),,H represents H,

I ammonium. For convenience, hydrogen will be used hereinafter as illustrative of these monovalent cations.

Illustrative of the lower alkylene groups represented by R above are methylene, ethylene, propylene, butylene, pentylene and the like. For convenience hereinafter methylene will be used as illustrative of the lower alkylene groups.

Accordingly, more specific types of compounds encompassed by Formulas I-III above are set forth below.

wherein A in each instance above is an anhydride or acid polymer fragment. In these polymeric structures, of course, the defined units are randomly occurring in the polymer chain and can occur in any sequence or combinations with the anhydride or acid formed by hydrolysis of the anhydride. In the instance ,wherein all of the anhydride functions are converted to the corresponding thio analogs then A will not be present and the polymer will be made up of the repeating defined units specified in the respective formulas above.

The novel compounds of this invention can be prepared directly from the copolymer precursor. For example, ethylene-maleic anhydride, propylene-maleic anhydride, isobutylene-maleic anhydride, styrenemaleic anhydride, or methyl vinyl ether-maleic unhydride copolymers as well as crosslinked copolymers. illustrative, the ethylene maleic anhydride copolymer will be used hereinafter. The ethylene-maleic anhydride copolymer can be prepared in accordance with any of the known prior art procedures. Ethylene and maleic anhydride copolymerize only in substantially equimolar proportions, even when one of the comonomers is present in excess. This reactivity would indicate that the structure of the copolymer is one of substantially uniform alternation of ethylene and maleic anhydride to form a polymer having a structure of the following form:

wherein n is an integer greater than 3. These maleic anhydride copolymers may also be crosslinked through their alkylene backbone.

From the precursor ethylene-maleic anhydride copolymer the compounds of this invention can be prepared in accordance with the following reaction scheme:

While a specific ethylene-maleic anhydride unit is employed in the reaction scheme above, it will be realized that this is somewhat simplified. The respective reactions can occur at any of the unit sites. The effective chain length of the products of this invention will be substantially the same as the precursor ethylenemaleic anhydride copolymer. Additionally, while the polymer products of this invention must have at least one thio conversion per molecule, 100 percent conversion is possible although it may not in all instances be practical in commercial operation.

The repeating units of the polymeric compounds as represented above by -n are generally from about 3 to about 10,000 inclusive although n preferably has a value of from about 25 to about 1,000 inclusive.

Considering each of the generic compounds set forth above independently, sodium sulfide or phosphorus pentasulfide can be employed in a stoichiometric amount based upon the weight of the ethylene-maleic anhydride copolymer precursor, although it is generally desirable to use this material in excess unless only a partial conversion to the thiol anhydride is desired.

Reaction A-B is preferably conducted in a polar, aprotic solvent medium such as acetonitrile, acetone, dimethylformamide, dioxane, dimethyl sulfoxide, dimethyl sulfone;dimethylacetamide, pyridine, xylene and the like. However, this reaction can also be conducted in the absence of a solvent medium by intimatevent are employed, then superatmospheric pressures.

must also be utilized and appropriate pressure equipment.

In respect to the preparation of generic compound C above, this is easily accomplished by treating compound B, the thiol anhydride, with hydrogen sulfide.

Compound B can be separated or the reaction mixture can be simply treated with hydrogen sulfide. The hydrogen sulfide can be used in stoichiometric amounts, although an excess is preferred unless a partial reaction is desired.

The hydrogen sulfide is effectively admixed with the precursor compound B, i.e., thiol anhydride, by dissolving the thiol anhydridein a suitable aprotic anhydrous solvent, such as has been described above, and sparging H S through this solution. Alternative techniques, of course, can be employed and elevated pressures can be utilized, if desired.

This reaction is preferably conducted at a temperature of from about -20 to about 200C. inclusive, although temperatures of from about 0 to about C. are preferred.

Compounds represented by formula D above can be prepared by dissolving the ethylene-maleic anhydride copolymer precursor in a suitable aprotic solvent and reacting this precursor with hydrogen sulfide. Again, the hydrogen sulfide is preferably sparged as a gas through the solution of precursor, although liquid hydrogen sulfide can also be used at temperatures below 0C and under superatmospheric pressures. It is preferred to employ an excess of the hydrogen sulfide reactant. Solvents which can be employed include any of the following: ethers, esters, hydrocarbons, nitriles, sulfides, carbon bisulfide, and the like.

These reactions are preferably conducted at temperatures of from about -40 to about 200C. Preferred temperatures are from about 20 to about 100C.

Compounds E and F above are prepared in a similar manner to compound B except that, as indicated, the starting material in this instance is compound D except that compound E, of course, can be converted to compound F as indicated. Phosphorus sulfide or sodium sulfide can effectively be employed as the sulfur donating reagent. The temperatures for this reaction range from about 25C. to about 200C. and preferably from about 50C. to about C. Aprotic solvents as indicated above can be employed to advantage in which case reflux temperatures can be employed. Temperatures in excess of reflux can be employed by fusion or autogeneous pressures.

reduced pressure. The crude reaction product is a highly viscous, hygroscopic material.

: EXAMPLE 3 maleic -anhydride) resin (Monsanto EMA-31) are dispersed in 100 ml of xylene. About 150 parts of powdered phosphorus pentasulfide is added, and the vigorously agitated dispersion is slowly brought up to reflux temperature. Reflux is continued for about four hours. A relatively pure poly (ethylene-maleic thiolanhydride) product is isolated from the xylene phase by liquid-liquid extraction techniques.

- EXAMPLE 4 Poly (ethylene-dithiolmaleic acid) The crude poly (ethylene-maleic thiolanhydride) resin obtained from Example 1 is dissolved in 800 parts of diglyme. At room temperature, this solution is saturated with hydrogen sulfide, a few drops of sulfuric acid are added and then the solution is brought to reflux temperature while fresh hydrogen sulfide is blown through the agitated solution at 40C. for 3 hours.

' Acetone solvent is then removed by distillation. The residual waxy, very light yellow colored reaction product is'analyzed by iodine titration and IR spectroscopy. It is found to contain thiolcarboxylic acid groups as postulated and only minor quantities of carvboxylic acid groups. I

EXAMPLE 5 Poly.(ethylenemaleic monothiolcarboxylic acid) By a procedure analogous to the method described in Example 4, poly (ethylene-maleic anhydride) (MonsantoEMA-21)'is thiolized with hydrogen sulfide in glyme to give-a polymericethylene-maleic monothiolcarboxylic'acid having a melting point 180C.

EXAMPLE6 The procedure. of Example 5 is repeated using a methylvinylether-maleic anhydride copolymer of the GAF Corporation (GANTREZ AN'resin). Polymeric (methylvinylether-maleic monothiolcarboxylic acid) is obtained in good purity after evaporating the solvent.

EXAMPLE 7 The reaction product of Example 5 is dissolved in water and neutralized with sodium hydroxide, to about pH 8. By removing water quantitatively at reduced pressure and elevated temperatures, the sodium salt of poly (ethylene-maleic thiolcarboxylic acid) is obtained in practical quantitative yield.

EXAMPLE 8 The reaction product of Example 5 is dissolved in dioxane and refluxed for six hours with agitationin the presence of a stoichiometric amount of powdered zinc oxide. After cooling the colorless zinc salt of poly (ethylene-maleic thiolcarboxylic acid) is isolated by filtration. The salt is purifiedby washing it with small amounts of cold water and with methanol.

About 100 parts of finelypowdered poly (ethylene- 5 EXAMPLE 9 Three parts of thereactio'n product of Example 3.are blended with 100 parts of PVC (Geon lQ3.EP), '1 part of stearic acid lubricant and 30 parts of DOP plasticizer. This blend-is fused onja two-roll chrome-' plated mill at 335F. for 30 minutes. The resulting flexible PVC film (12 mils) is clear and practically colorless. When the same experiment is run using the corresponding precursor anhydride resin instead of the poly-thiolanhydride of Example 3,.strong discoloration of the film begins after a few. minutes.

EXAMPLE 10 wherein R is a lower alkylene group of-from one to five carbon atoms inclusive, a is an integerhaving a value of from 0 to l, b is an integer having a value of from 0 to 1, such that when a equals 1, b also equals 1, n represents the number" of repeating units and Y is a chalcogen having a molecular weight less than 34 with the proviso that at least one Y'per molecule must be sulfur. v Y I I g 2. The composition .of claim 1 wherein 'thevinyl polymer is a vinyl chloride polymer.

3. A polymericcomposition containing a mixture of a vinyl polymer and a stabilizing amount of a polymeric compound having the formula:

(O)n(C]Iz) l[ I nur-oir-wira wherein R is alower alkylene group of from 1 to 5 carbon atoms inclusive, a is an integer having a value of from 0 to l, b is an integer having a value of from 0 to 1 such that when a equals l,'b also equals 1, M is a monovalent'cation having a molecular weightless than 40, Y is a chalcogen havinga molecular weight less than 34 with the proviso that at least one Y per molecule must be sulfur and n is the number of repeating units of the molecule.

4. The composition of claim 3 wherein the vinyl polymeris a vinyl chloride polymer.

5. A polymeric composition containing a mixture of a vinyl polymer and a stabilizing amount of a polymeric compound having the formula:

L Ya...

' vinyl Ethylene-maleic anhydride copolymers containing the units represented by formulas B, C, D, E, and F above have found particular utility as stabilizers for vinyl polymers most particularly vinyl chloride polymers wherein the polymer contains a predominant amount of polymerized vinyl chloride monomer. When used in this application, it can be used directly as the thiolanhydride B, which is preferred, or it can be used as the mixed thio-oxo-a'cids (B,D,E and F) or thio acid per se. In respect to the mixed thio-oxo-acids represented by formulas C, D, E, and F, these compounds can be employed also as salts. In this respect, it is desirable to employ the zinc, calcium, cadmium, barium, strontium, and tin or organo tin salts.

Compounds D, C, E, and F above, particularly the higher molecular weight compounds, i.e., where n is an integer of from about 100 to about 10,000 inclusive, are particularly useful as ion exchange resins with particular selectivity to the noble metals especially those of the platinum group as well as silver, gold and nickel.

Compounds represented by formulas B, C, D, E and F above also serve effectively as rubber curing agents and accelerators.

Additionally the novel compositions of this invention can be used as resin binders, in surface coatings, as detergent builders, as thickeners, as cutting fluids, as pigment dispersants and as paper and textile sizes and finishes.

In respect to the use of these compounds as stabilizers for vinyl chloride resins, it is intended that vinyl chloride resins include both the homopolymers as well as copolymers with other copolymerizable vinyl monomers.

'By the term vinyl polymers is intended polymers containing polymerized vinyl monomers having the structure Such monomers generally contain from two to about 18 carbon atoms, inclusive, and can be illustrated by the following: Lower 01 -olefin monomers such as ethylene, propylene, butene, and the like; the aromatic vinyl monomers such as styrene, a -methyl styrene,

1 chlorostyrene, and the like; vinyl and vinylidene halides such as vinylv chloride, vinyl fluoride, vinylidene chloride, vinylidene bromide, and the like; vinyl esters such as vinyl formate, vinyl acetate, vinyl propionate,

butyrate, vinyl chloroacetate, vinylchloropropionate, and the like; acrylic and alphaalkyl acrylic acids, their amides, and their nitriles such as acrylic acid, chloroacrylic acid, methacrylic acid, ethacrylic acid, methyl acrylate, ethyl acrylat e, butyl I acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, n-

decyl acrylate, methyl methacrylate, butyl methacrylate, methyl ethacrylate, ethyl ethacrylate, acrylamide,

N-methyl acrylamide, N ,N-di-methylacrylamide, methacrylamide, N-methyl methacrylamide, N,N- dimethylmethacrylamide, acrylonitrile,

chloroacrylonitrile, methacrylonitrile, ethacrylonitrile, and the like; maleic and fumaric acids, and their esters such as dimethyl maleate, diethyl maleate, monobutyl maleate and the like; vinyl alkyl ethers and ketones such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, 2-chloroethyl vinyl ether, methyl vinyl ketone, ethyl vinyl ketone, isobutyl vinyl ketone, and the like; N-methyl-N-vinyl acetamide, N-vinyl carbazole, N-vinyl pyrrolidone, ethyl methylene malonate I and the like.

The term vinyl polymers is intended to include both homopolymers of such vinyl monomers as well as the vinyl copolymers formed by the interpolymerization of two or more of the copolymerized vinyl monomers.

When used as a stabilizer in such use it is desirable to employ a stabilizing amount. This amount is generally from about 0.5 to about 5.0 percent by weight based upon the vinyl chloride resin employed, but larger amounts can also be used effectively if desired.

In respect to the ethylene-maleic anhydride copolymer employed as precursor, there will be a wide degree of variation in molecular weight dependent upon the molecular weight of this precursor. The higher molecular weight polymers and cross linked polymers tend to be less soluble in conventional solvents and the viscosity of solutions of such polymers are markedly higher than solutions of the lower molecular weight polymers. The higher molecular weight polymers are accordingly more difficult to formulate. In general, the preferred materials for vinyl resin stabilization are those having molecular weights such that the polymers have a specific viscosity below about cps. when measured as a one-weight percent solution in dimethyl formamide at 25C.

When the compounds of this invention are employed as stabilizers in vinyl chloride polymers such as polyvinyl chloride, vinyl chloride-vinyl acetate copolymers, vinyl chloride-acrylonitrile copolymers and the like, they can effectively be employed with other stabilizers and antioxidants. Conventional stabilizers which can be used as co-stabilizers are the barium, cadmium, zinc and calcium salts of fatty acids such as the stearates, laurates, oleates, and the like; the tin stabilizers such as butyl stannoic acid; organo phosphites and sulfites.

In the examples which follow and throughout the specification, all parts and percentages are by weight unless specifically indicated to the contrary.

EXAMPLE 1 give a fine, light yellow solid product. Spectrographic, I

elemental and titrimetric analyses show that most of the anhydride functions are converted to thiolcarboxylic anhydride. The crude product is protected from exposure to moisture or bright sun light. It exhibits a slight mercaptan-type odor.

EXAMPLE 2 Example I is repeated using parts of P,S, instead of Na,S. A minor amount of hydrogen sulfide evolved which is removed from the mixture by applying wherein R is a lower alkylene group of from one to five carbon atoms inclusive, a is an integer having a value of from to 1 and b is an integer having a value of from 0 v to i such that when a equals 1, b also equals 1, M is a monovalent cation having a molecular weight less than 40, Y and Y are chalcogens having molecular weights less than 34 with the proviso that at least one substituent per molecule must be and n is the number of repeating units in th molecule. I

6. The composition of claim 5 wherein the vinyl I 9. The composition of claim pl wherein R is methylene a and b equal 0, n isfan integer having at value of from about 25 to about 1,000in'clusive and M is hydrogen or sodium.

' a a: a: i a:

$222 3 UNlTED STA'KES PATENT OFFICE CERTIFICATE @F CQRRECTFQN- Patent No. 5,7 5 Dated April 5, 975

Inventcfls) Walter Stamm- It is certified that error appears in the above-identified patent and that said Letters Patent are hereby correct ed as shown below:

column 8, line 6%, the first formula in claim 5, delete"(O) -(CN H" and insert (O) (CH H Column 9 line 8, the second formula in claim 5, delete Y1 Y] Y H -C and insert -C- Column 10, line 12,- in claim 9, the dependency should be changed from claim l" to claim 6 1 Signed and sealed this 19th day of March 197M.

(SEAL) Attest:

EDWARD M. FLETCHER, JR. Ca MARSHALL DANN Attesting Officer Commissioner of Patents 

2. The composition of claim 1 wherein the vinyl polymer is a vinyl chloride polymer.
 3. A polymeric composition containing a mixture of a vinyl polymer and a stabilizing amount of a polymeric compound having the formula:
 4. The composition of claim 3 wherein the vinyl polymer is a vinyl chloride polymer.
 5. A polymeric composition containing a mixture of a vinyl polymer and a stabilizing amount of a polymeric compound having the formula:
 6. The composition of claim 5 wherein the vinyl polymer is a vinyl chloride polymer.
 7. The composition of claim 2 wherein R is methylene, a and b equal 0, and n is a value of from about 25 to about 1,000 inclusive.
 8. The composition of claim 4 wherein R is methylene, a and b equal 0, n is an integer having a value of from about 25 to about 1,000 inclusive, and M is hydrogen or sodium.
 9. The composition of claim 1, wherein R is methylene a and b equal 0, n is an integer having a value of from about 25 to about 1,000 inclusive and M is hydrogen or sodium. 